Method for the production of yarn and a yarn obtained by applying the said method



June 3, 1969 c. BOK ETAL 3,447,310

METHOD FOR THE PRODUCTION OF YARN AND A YARN OBTAINED BY APPLYING THESAID METHOD Filed June 20, 1967 4 rra/m zfrs United States Patent US.Cl. 57-164 7 Claims ABSTRACT OF THE DISCLOSURE A method for theproduction of untwisted yarn from staple fibre material. A rovingorsliver is brought into a wet condition and is, under maintenance ofthe wet condition, subsequently drawn at a high speed to form a thinsliver, false-twisted and cross-wound into a fibre packet. By sizingthis fibre packet an unwindable yarn packet is obtained, the yarn beingsuitable for weaving like conventional twisted yarn.

The present invention relates to a method for the production of yarnfrom a roving of staple fibre material. Here and hereinafter the wordroving is understood to include twist-free or substantially twist-freefibrous slivers,

which are adapted to be worked up into a final yarn.

Many variants of such methods are known and they consist in drawing androving to form a thin fibrous sliver by means of a drawing device and intwisting of the sliver delivered by the drawing device by means of atwisting winding device.

In the manufacture of yarn it is aimed at to come to lower productioncosts by speeding up the tempo of production. This makes it necessaryfor the number of revolutions of the twisting winding device, forexample the spinning spindle of a ring spinning machine, to be increasedlikewise. As a matter of fact, this number of revolutions is determinedby the product of the delivery speed of the drawing device in metres perminute and the number of twist turns per metre which is required to givethe yarn the desired properties.

In practice, the allowable number of revolutions of the spinningspindles and the like is found to form the limitation to the speed withwhich the yarn can be produced.

Revolution numbers up to 20,000 revolutions per minute are already beingused and by this means a yarn production of 40 111. per minute can bereached, but, although owing to the progressive refinement of techniquea further increase of the allowable number of revolutions is notexcluded, yet this matter continues to form a decisive impediment to anyimportant increase of the speed of production.

Another limitation of production speed is met with in drawing the rovingto form a thin fibrous sliver. When the speed of the delivery rollers ofthe drawing device is too high, the fibres are torn from the rovingsupplied by the feeding rollers at such a rate as to cause a disruptionof the coherence among the fibres giving rise to interruptions in thefibrous sliver, which means ruptures in the yarn.

These difiiculties have to a certain degree been met by applying variousmeasures directed to the improvement of the coherence of the fibresamong themselves during the drawing process, such as extra rollers,belts and the duction speed and by using which a considerable increaseof the velocity can, therefore, be realized.

For this purpose, the method according to the present invention has thecharacterizing feature that the roving is subjected to a number oftreatments, among which the treatments that are of importance for yarnformation exclusively consist in bringing the roving into a wetcondition,'drawing the said roving at a great speed to form a thinnerfibrous sliver, false-twisting the said fibrous sliver, winding thefibrous sliver into a fibre packet in the shape of a cross-wound bobbinand sizing the fibre packet so as to form an unwindable yarn packet.

In this connection it is observed that a wet condition of fibrousmaterial is understood to mean the presence of so much water as to haveit adhering to the surface of the fibres as free water, such incontradistinction to a humid condition, in which the water has beenentirely absorbed by the fibres. By a cross-wound bobbin is understood acoil the turns of which only touch each other when crossing.

In this method, no use is made of a twisting winding device, so that inthis respect the production speed does not meet with any impediments andis only limited by the cross-winding, which allows of a much greaterwinding velocity.

As it has surprisingly been found, the fibres, owing to the roving beingdrawn in wet condition, show such a firm coherence as to make itpossible for an uninterrupted and smooth thin sliver to be formedspecially at high delivery speeds of the drawing device and thesmoothness of the yarn improves as the speed increases. This may perhapsbe attributed to, forces of mass inertia, viscous forces and surfacetensions, which cause more regular differences in speed between thefibres while being drawn. With this in view, drawing is effected at adelivery speed of at least 50 m. per minute.

It is not necessary for the drawing of the roving that the water to beused for wetting the fibrous material should contain dissolved orsuspended additives. It is possible, however, to use such additives witha view to later treatments of the yarn or for the obtention of specialproperties.

According to a further feature of the method according to the invention,the drawing of the roving is effected on a drawing device comprising twoor more pairs of rollers and in which the roving runs between twosuccessive pairs of rollers through a free drawing field. As a matter offact, it has been proved by experiments that the provisions usuallypresent in the drawing field, such as needles, pins, rollers and belts,which serve the purpose of increasing the coherence among the fibreswhile being drawn, exert an adverse influence on the drawing process andon the quality of the yarn where the method according to the presentinvention is concerned.

The false-twisting causes the coherence of the fibres to be temporarilyincreased after drawing to such an extent as to render the sliver strongenough to cover the distance between the drawing device and the windingdevice and to resist any tensile stresses it may meet with on its way.

It is usual for a pneumatic false-twisting device to be employed infalse-twisting. For this purpose, the fibrous sliver is guided through amainly cylindrical bore, into which a number of blowing nozzles open ina tangential way. In this manner a rotating air column forms within thebore, the rotation of the said air column being transmitted on to thepassing sliver. The number of its revolutions may easily be increased tosuch an extent that in this respect no limitation Whatever of the speedof the yarn is met with.

The absence of speed limitations to which the known methods are subject,has the result that the method according to the present inventionpermits of relatively very high velocities. It has been found that avelocity of, for instance, 400 111. per minute may easily be applied andconsiderably higher speeds are simply counted among the possibilities ofthe method according to this invention.

While winding the thin sliver that has been formed into a fibre packet,it is of importance that no part of the sliver should anywhere betouched in a parallel way by another part of the sliver, because, afterthe sizing, these two parts of the sliver would be connected together sofirmly that yarn rupture would almost certainly occur in this place whenthe yarn was being unwound. For this reason, it is necessary to use thecross-Wound bobbin, the turns of which touch each other at the crossingsonly, as the winding form of the sliver, because it has been found thattwo sliver parts that cross each other, after they have been sized willnot form a connection, which is stronger than the yarn itself.

The sizing can be effected by using a perforated core when winding thefibre packet and by introducing the sizing agent into the packet bymeans of this core. However, when using this method, it is difiicult toobtain an even concentration of the sizing agent in the packet and tomaintain it. Specially when the obvious sizing agents on basis of starchare used, the drying process, during which hot air is blown through thepacket by way of the core, will give rise to migration phenomena, withthe result that the content in sizing agent of the yarn can not have thedesired value in all places.

In order to improve the situation, the method according to the presentinvention is preferably carried out in such a way that the sizing agentrequired for the sizing of the fibre packet is added to the roving in anon-active form and that the fibre packet is subsequently subjected to atreatment that activates the sizing agent.

This can be realized by bringing the sizing agent on one or more of thedelivery rollers of the drawing device, so that the fibrous materialwill absorb the sizing material while passing the delivery rollers.

Another possibility is that, for instance, when starch is being used asthe sizing agent, the roving, which is in an unsaturated wet condition,is washed with an excess supply of starch-grain suspension, after whichthe fibre packet is subjected to a heat treatment, the temperature, theenvironmental moisture and the duration of which are adapted to thegelatination of the starch grains present in the fibre packet, andsubsequently dried. A combination of these two methods is also possible.As has been found, these methods do not give rise to any migrationphenomena of the starch in the packet.

The method according to the invention offers the additional advantagethat any further treatments of the fibrous material that may benecessary, such as bleaching, dyeing, mercerizing, or rendering thematerial self-ironing (no iron), fire-resistant or rotproof, can becarried out while it is still in the roving stage, so that thesetreatments can work themselves out more fully and sometimes can becarried out in a more economical way, because the roving is already inthe wet condition in view of the further working-up into yarn.

The yarn which is obtained by the method according to the presentinvention is twistfree or, such in connection with the twist of theroving and the twist which may have been given to the yarn through theunwinding of the packet in axial direction, substantially twist-free.The coherence among the fibres is entirely obtained by means of theglueing and is so strong that the yarn can be used as a weaving yarnjust as the usual twisted yarns. This implies that a cotton yarnmanufactured according to method of the present invention canimmediately be used as a warp yarn, whilst a woollen yarn has only to bedoubled in the usual manner to obtain the resistance against wear andshock required in a warp yarn.

Besides for cotton and woollen yarns, the method according to thisinvention may also be used for yarns made of other fibrous materials andfor yarns consisting of mixtures of different fibres.

This invention also relates to yarns which have been manufactured byusing the above-described method. It is distinguished from twistedyarns, besides by its entire or substantially entire lack of twist, byits somewhat flat-cross section. When it is used as a single warp yarn,this flatness has the advantage that it easily passes the healds and thereed of the weaving loom and, because it comes to lie flat in the web,it has the effect that the web is of a closer structure than is anotherwise similar fabric of twisted yarn.

In the following, the invention will be elucidated with reference to theaccompanying drawing which shows a diagram of the arrangement of aspinning machine, and to an example.

The roving 1, which is pulled off the wet roving bobbin 2, is guidedalong some guiding elements 3 towards a drawing device, the feedingroller set of which is formed by the serrated roller 4 and the rubberroller 5 and the delivery roller set of which is formed by the serratedroller 6 and the rubber roller 7. Here, the roving 1 is drawn to formthe thin fibrous sliver 8, which subsequently passes the pneumatictwisting element 9 and the traversing element 10 and is wound up to forma fibre packet 11, which is driven -by the winding roller 12.

While passing the guiding elements 3, the roving is washed with asuspension of potato starch in water, which is supplied from thereservoir 15 through the pipe 13 with the control cock 14. An agitator16 is provided in the reservoir to prevent the suspension fromsedimenting.

The suspension from the reservoir 15 is also supplied to the deliveryrollers of the drawing device through the same pipe 17 with the controlcock 18. For this purpose, a circulating band 20 is provided about therollers 19, one of which is driven by the feeding roller set in thedirection indicated at a low speed. The band 20, which presses againstthe roller 7, brings a thin layer of the suspension, which is suppliedthrough the pipe 17, on to the roller 7, which in turn transmits part ofthis layer to the fibrous sliver 8.

The excess of the suspension, which is supplied through the pipes 13 and17, is collected in the basin 21, whence it is recycled by the pump 23through the pipe 22 to the reservoir 15.

The suspension-content gauge 24 is provided in the pipe 17, by whichgauge changes of the suspension can be established and, if necessary,corrected.

When carrying out the method according to this invention, a cottonroving of 300 tex was wound on roving bobbins, brought into a wetcondition by boiling off and defattened and subsequently bleached anddyed. The moisture content was reduced to about by means of suction.

Being in this condition, the roving was unwound from the bobbins and,after having been washed by the stream of a suspension of 10% of potatostarch in water issuing from the pipe 13, it was taken through thedrawing device. The compressive force of the feeding rollers amounted toabout 1 kg., so that the roving, after it had passed these rollers, hada moisture content of about The drive of the drawing device was arrangedin such a manner that the peripheral velocity of the delivery roller setwas 15 times as high as that of the feeding roller set and amounted toabout 200 m./minute.

The fibrous sliver having a thickness of 20 tex which issued from thedrawing device, was taken through the pneumatic twisting element at thissame velocity. This twisting element consisted of a cylindrical channelhaving a length of 6 mm., a diameter of 1.5 mm. and bevelled end parts,and 6 tangential blowing nozzles having a diameter of 0.4 mm. each andhaving an axial deviation of 5 in the running direction of the yarn. Thetwisting element was fed with air of 0.4 atmosphere, the air consumptionamounting to about 7 l./min.

After having passed the twisting element, the sliver was wound up on aperforated core in the shape of a crosswound bobbin. The peripheralvelocity of the driving roll was about 3% lower than the velocity ofdelivery of the drawing device, so that unaJlowable tensions in thefibrous sliver were avoided.

After the sliver had in this way been formed into a packet, the latterwas taken from the core and was subjected to a treatment with lowpressure steam in an air-free space for 30 minutes. The packet wassubsequently dried, after which the sized yarn could be unwound from thepacket.

It appeared that the yarn contained about 16% of adhesive.

Working experiments went to show that the yarn could normally be usedfor weaving without presenting any difficulties. It was found that afabric made from this yarn had mechanical properties, which were in norespect unfavourable as compared with a similar fabric made from a yarnmanufactured in a conventional way, not even after the sizing agent hadbeen washed out of the fabric, this being indicative of the fact thatthe coherence among the fibres was produced by the structure of thefabric and was not dependent on the structure (twist) of the yarn. Itwas also found that the fabric, after a pertinent aftertreatment, wasconsiderably less air permeable and had a substantially betterwatertightness than comparable fabrics made from yarns produced in theconventional way.

We claim:

1. A method for the production of yarn from a roving of staple fibrematerial having insufficient natural sizing agents to be able to form atwist-free yarn, wherein the roving is subjected to a number oftreatments, among which the treatments that are of importance for yarnformation exclusively consist in bringing the roving into a wetcondition, drawing the said roving at a great speed to form a thinnerfibrous sliver, false-twisting the said fibrous sliver, winding thefibrous sliver into a fibre packet in the shape of a cross-wound bobbinand sizing the fibre packet so as to form an unwindable yarn packet.

2. A method according to claim 1, in which the drawing of the roving iseffected on a drawing device comprising two or more pairs of rollers,wherein the roving runs between two successive pairs of rollers througha free drawing field.

3. A method according to claim 1 wherein the sizing agent required forthe sizing of the fibre packet is added to the fibre material in anon-active form and that the fibre packet is subjected to a treatmentthat activates the sizing agent.

4. A method according to claim 3, wherein the sizing agent is added tothe fibrous material by means of at least one of the rollers of thedelivery roller set.

5. A method according to claim 3, wherein the roving, which is in anunsaturated wet condition, is washed with an excess supply ofstarch-grain suspension and that the fibre packet is subjected to a heattreatment, the temperature, the environmental moisture and the durationof which are adapted to the gelatination of the starch grains present inthe fibre packet, and is subsequently dried.

6. A method according to claim 3 wherein said sizing agent is added tothe fiber material as an aqueous solution or suspension prior to thefalse twisting of said roving.

7. A method according to claim 6, wherein the nonactive but activatablesizing agent applied to the roving is a starch-grain suspension andwherein the fiber packet is subjected to heat treatment, thetemperature, the environmental moisture and the duration of which isadapted to gelatinize the starch-grains present in the packet, andsubsequently drying said fiber packet.

References Cited UNITED STATES PATENTS 1,051,361 1/1913 Young et al 1966XR 1,905,268 4/1933 Cotchett 19-66 1,959,723 5/1934 Le Jeune et a1. 5736XR 2,154,675 4/1939 Foster 57164 2,366,785 1/ 1945 Hays 19-66 XR2,493,359 1/1950 Painter 5735 2,671,304 3/1954 Roedder 5735 XR 3,310,9353/1967 Wurzburg et al 57164 OTHER REFERENCES 1,137,361, Germany, Tissotet al., 57/ 164, publ. September 1962.

STANLEY N. GILREATH, Primary Examiner.

W. H. SCHROEDER, Assistant Examiner.

US. Cl. X.R. 1966; 5735, 36

